Predictive Value of Circulating Insulin-Like Growth Factor I Levels in Ischemic Stroke Outcome

Abstract

CONTEXT: Cerebrovascular disease is highly prevalent in the general population, frequently leading to permanent invalidity and reduced quality of life. IGF-I is recognized as an important neuroprotective factor against cerebral hypoxic insult. OBJECTIVE: The objective of the study was to evaluate pituitary function, in particular GH-IGF-I axis, in adult patients receiving rehabilitation after an ischemic stroke. SUBJECTS AND METHODS: We studied 42 patients (12 females; age range, 50-88 yr) during rehabilitation after stroke, evaluating the relationship between the GH-IGF-I axis and the severity (National Institutes of Health stroke scale) and outcome [Rancho Los Amigos Scale of Cognitive Functioning (LCFS); Functional Independence Measure (FIM); modified Ranking Scale] from stroke. RESULTS: GH deficiency was demonstrated in five patients (11.9%). Peak GH after GHRH + arginine test and IGF-I levels did not correlate with severity of stroke. IGF-I was positively correlated with LCFS (r = 0.305, P < 0.05) and the difference between FIM on admission and at discharge from rehabilitation (DeltaFIM; r = 0.361, P < 0.02). Outcome indexes (LCFS, FIM at discharge, DeltaFIM) and occurrence of favorable outcome (modified Ranking Scale 0-1) were significantly (P < 0.05) higher in patients with IGF-I levels 161.8 mug/dl or greater (50th percentile of the patient distribution). LH-FSH deficiency (three cases), ACTH deficiency (one case), and hyperprolactinemia (two cases) were detected. One patient had primary hypogonadism, and six males had low testosterone with normal LH and FSH levels. By multivariate analysis, IGF-I level was the main significant predictor of DeltaFIM and LCFS. CONCLUSIONS: Ischemic stroke may be associated with pituitary dysfunction, particularly GH and gonadotropin deficiencies. The higher IGF-I levels observed in patients with better outcome suggest a possible neuroprotective role of IGF-I. Circulating IGF-I may predict functional performance during rehabilitation and ischemic stroke outcome.